1. Field of the Invention
The invention generally relates to the field of photographic camera shutters. More particularly, the invention relates to a camera shutter of the type wherein a latch for arresting shutter opening and closing blades in respective cocked positions is operated to release the blades in succession to open and close the shutter.
2. Description of the Prior Art
FIGS. 1-4 of the accompanying drawings illustrate a prior art example of a camera shutter of the type wherein (a) shutter opening and closing blades 1 and 3 are urged by respective springs 5 and 7 to pivot from cocked positions in FIG. 1 to uncover an objective lens 9 in FIG. 3 and to recover the lens in FIG. 4 and (b) a latch 11 is pivoted initially by a manually operated shutter release member from a first or original position in FIG. 1 for arresting the opening and closing blades in their cocked positions, to a second position in FIG. 2 for releasing the opening blade, and to a third position in FIG. 3 for releasing the closing blade. When the latch 11 is pivoted from its first position to its second position, a blade engaging member 13 of the latch clears a relatively shallow notch 15 in the opening blade 1 to release the opening blade. See FIG. 2. However, the blade engaging member 13 does not clear a deeper notch 17 in the closing blade 3 and, therefore, retains the closing blade in its cocked position. The opening blade 1 includes a trailing cam edge portion 19 which forces the blade engaging member 13 out of the deeper notch 17 in the closing blade 3, to release the closing blade, as the opening blade is pivoted to uncover the objective lens 9. See FIG. 3. Thus, the opening and closing blades 1 and 3 are released by the latch 11 in succession to uncover and recover the objective lens 9.
Although a camera shutter of the type illustrated in FIGS. 1-4 of the accompanying drawings is known to perform in a satisfactory manner, it may be possible in a particular instance for the latch 11 to be moved from its first or original position immediately to its third position, thereby releasing the closing blade 3 too soon after the opening blade 1 is released.